1. Field of the Invention
The present invention relates in general to a magnetic head core which includes two ferrite members forming an annular, closed magnetic circuit, and in particular to a novel structure of such a magnetic head core which assures a reduced inductance and is suitably used with a recent magnetic recording medium having a relatively high recording density.
2. Discussion of the Related Art
To meet an increasing requirement for a high recording density of a magnetic recording medium, such as a floppy disk, a magnetic disk and a magnetic tape, there has been much research and development activity particularly on a rigid magnetic disk drive which permits an increased density of information to be recorded per unit area of the magnetic recording medium, in an effort to realize a compact, high capacity and high-speed disk drive.
A type of magnetic head used with a rigid disk drive (RDD), hard disk drive (HDD), floppy disk drive (FDD) and other devices has a magnetic head core, which includes a first ferrite member and a second ferrite member butted and bonded together to form an annular, closed magnetic path having a coil-winding aperture. The magnetic head core has a disk-sliding surface to be opposed to a magnetic recording medium, which surface is formed to extend across the two ferrite members. A coil is wound around the first ferrite member of the head core.
However, the magnetic head core in which the annular, closed magnetic path is formed by the ferrite members suffers from undesirably high inductance, and cannot use high-frequency signals due to a limited resonance frequency. Thus, the known magnetic head core does not satisfy the requirement for high recording density of the magnetic recording medium.
The inductance of the magnetic head core can be effectively reduced by reducing a cross sectional area of the ferrite members forming the magnetic path, as disclosed in JP-A-3-283008 filed by the assignee of the present application. However, it is difficult to reduce the cross sectional area of the ferrite members sufficiently since the ferrite members are fragile and the head core needs to be strong enough to endure stresses applied when the coil is wound around one of the ferrite members. Thus, it is extremely difficult for the known magnetic head core to exhibit a sufficiently low inductance.